---
title: Behavior Configuration
sidebar_label: Behaviors
---

Some behaviors have properties to adjust how they behave. These can also be used as templates to create custom behaviors when none of the built-in behaviors do what you want.

See [Configuration Overview](index.md) for instructions on how to change these settings.

See the [zmk/app/dts/behaviors/](https://github.com/zmkfirmware/zmk/tree/main/app/dts/behaviors) folder for all default behaviors.

## Common

### Kconfig

| Config                            | Type | Description                                                                          | Default |
| --------------------------------- | ---- | ------------------------------------------------------------------------------------ | ------- |
| `CONFIG_ZMK_BEHAVIORS_QUEUE_SIZE` | int  | Maximum number of behaviors to allow queueing from a macro or other complex behavior | 64      |

## Caps Word

Creates a custom behavior that behaves similar to a caps lock but deactivates when any key not in a continue list is pressed.

See the [caps word behavior](../behaviors/caps-word.md) documentation for more details and examples.

### Devicetree

Definition file: [zmk/app/dts/bindings/behaviors/zmk,behavior-caps-word.yaml](https://github.com/zmkfirmware/zmk/blob/main/app/dts/bindings/behaviors/zmk%2Cbehavior-caps-word.yaml)

Applies to: `compatible = "zmk,behavior-caps-word"`

| Property         | Type   | Description                                                        | Default                         |
| ---------------- | ------ | ------------------------------------------------------------------ | ------------------------------- |
| `label`          | string | Unique label for the node                                          |                                 |
| `#binding-cells` | int    | Must be `<0>`                                                      |                                 |
| `continue-list`  | array  | List of [key codes](/docs/codes) which do not deactivate caps lock | `<UNDERSCORE BACKSPACE DELETE>` |
| `mods`           | int    | A bit field of modifiers to apply                                  | `<MOD_LSFT>`                    |

`continue-list` is treated as if it always includes alphanumeric characters (A-Z, 0-9).

See [dt-bindings/zmk/modifiers.h](https://github.com/zmkfirmware/zmk/blob/main/app/include/dt-bindings/zmk/modifiers.h) for a list of modifiers.

You can use the following nodes to tweak the default behaviors:

| Node         | Behavior                               |
| ------------ | -------------------------------------- |
| `&caps_word` | [Caps Word](../behaviors/caps-word.md) |

## Hold-Tap

Creates a custom behavior that triggers one behavior when a key is held or a different one when the key is tapped.

See the [hold-tap behavior documentation](../behaviors/hold-tap.md) for more details and examples.

### Devicetree

Definition file: [zmk/app/dts/bindings/behaviors/zmk,behavior-hold-tap.yaml](https://github.com/zmkfirmware/zmk/blob/main/app/dts/bindings/behaviors/zmk%2Cbehavior-hold-tap.yaml)

Applies to: `compatible = "zmk,behavior-hold-tap"`

| Property                     | Type          | Description                                                                               | Default            |
| ---------------------------- | ------------- | ----------------------------------------------------------------------------------------- | ------------------ |
| `label`                      | string        | Unique label for the node                                                                 |                    |
| `#binding-cells`             | int           | Must be `<2>`                                                                             |                    |
| `bindings`                   | phandle array | A list of two behaviors (without parameters): one for hold and one for tap                |                    |
| `flavor`                     | string        | Adjusts how the behavior chooses between hold and tap                                     | `"hold-preferred"` |
| `tapping-term-ms`            | int           | How long in milliseconds the key must be held to trigger a hold                           |                    |
| `quick-tap-ms`               | int           | Tap twice within this period (in milliseconds) to trigger a tap, even when held           | -1 (disabled)      |
| `global-quick-tap`           | bool          | If enabled, `quick-tap-ms` also applies when tapping another key and then this one.       | false              |
| `retro-tap`                  | bool          | Triggers the tap behavior on release if no other key was pressed during a hold            | false              |
| `hold-trigger-key-positions` | array         | If set, pressing the hold-tap and then any key position _not_ in the list triggers a tap. |                    |

The `flavor` property may be one of:

- `"hold-preferred"`
- `"balanced"`
- `"tap-preferred"`
- `"tap-unless-interrupted"`

See the [hold-tap behavior documentation](../behaviors/hold-tap.md) for an explanation of each flavor.

`hold-trigger-key-positions` is an array of zero-based key position indices.

You can use the following nodes to tweak the default behaviors:

| Node  | Behavior                                      |
| ----- | --------------------------------------------- |
| `&lt` | [Layer-tap](../behaviors/layers.md#layer-tap) |
| `&mt` | [Mod-tap](../behaviors/mod-tap.md)            |

## Key Repeat

Creates a custom behavior that repeats the whatever key code was last sent.

See the [key repeat behavior](../behaviors/key-repeat.md) documentation for more details and examples.

### Devicetree

Definition file: [zmk/app/dts/bindings/behaviors/zmk,behavior-key-repeat.yaml](https://github.com/zmkfirmware/zmk/blob/main/app/dts/bindings/behaviors/zmk%2Cbehavior-key-repeat.yaml)

Applies to: `compatible = "zmk,behavior-key-repeat"`

| Property         | Type   | Description                      | Default           |
| ---------------- | ------ | -------------------------------- | ----------------- |
| `label`          | string | Unique label for the node        |                   |
| `#binding-cells` | int    | Must be `<0>`                    |                   |
| `usage-pages`    | array  | List of HID usage pages to track | `<HID_USAGE_KEY>` |

For the `usage-pages` property, use the `HID_USAGE_*` defines from [dt-bindings/zmk/hid_usage_pages.h](https://github.com/zmkfirmware/zmk/blob/main/app/include/dt-bindings/zmk/hid_usage_pages.h).

You can use the following nodes to tweak the default behaviors:

| Node          | Behavior                                 |
| ------------- | ---------------------------------------- |
| `&key_repeat` | [Key repeat](../behaviors/key-repeat.md) |

## Macro

Creates a custom behavior which triggers a sequence of other behaviors.

See the [macro behavior](../behaviors/macros.md) documentation for more details and examples.

### Kconfig

| Config                             | Type | Description                            | Default |
| ---------------------------------- | ---- | -------------------------------------- | ------- |
| `CONFIG_ZMK_MACRO_DEFAULT_WAIT_MS` | int  | Default value for `wait-ms` in macros. | 15      |
| `CONFIG_ZMK_MACRO_DEFAULT_TAP_MS`  | int  | Default value for `tap-ms` in macros.  | 30      |

### Devicetree

Definition file: [zmk/app/dts/bindings/behaviors/zmk,behavior-macro.yaml](https://github.com/zmkfirmware/zmk/blob/main/app/dts/bindings/behaviors/zmk%2Cbehavior-macro.yaml)

| Property         | Type          | Description                                                                                                                                  | Default                            |
| ---------------- | ------------- | -------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------- |
| `label`          | string        | Unique label for the node                                                                                                                    |                                    |
| `compatible`     | string        | Macro type, **must be _one_ of**:<br/>• `"zmk,behavior-macro"`<br/>• `"zmk,behavior-macro-one-param"`<br/>• `"zmk,behavior-macro-two-param"` |                                    |
| `#binding-cells` | int           | Number of params accepted (depends on `compatible` property), **must be _one_ of**:<br/>• `<0>`<br/>• `<1>`<br/>• `<2>`                      |                                    |
| `bindings`       | phandle array | List of behaviors to trigger                                                                                                                 |                                    |
| `wait-ms`        | int           | The default time to wait (in milliseconds) before triggering the next behavior.                                                              | `CONFIG_ZMK_MACRO_DEFAULT_WAIT_MS` |
| `tap-ms`         | int           | The default time to wait (in milliseconds) between the press and release events of a tapped behavior.                                        | `CONFIG_ZMK_MACRO_DEFAULT_TAP_MS`  |

### Macro Control Behaviors

The following macro-specific behaviors can be added at any point in the `bindings` list to change how the macro triggers subsequent behaviors.

| Behavior                   | Description                                                                                                          |
| -------------------------- | -------------------------------------------------------------------------------------------------------------------- |
| `&macro_tap`               | Switches to tap mode                                                                                                 |
| `&macro_press`             | Switches to press mode                                                                                               |
| `&macro_release`           | Switches to release mode                                                                                             |
| `&macro_pause_for_release` | Pauses the macro until the macro key itself is released                                                              |
| `&macro_wait_time TIME`    | Changes the time to wait (in milliseconds) before triggering the next behavior.                                      |
| `&macro_tap_time TIME`     | Changes the time to wait (in milliseconds) between the press and release events of a tapped behavior.                |
| `&macro_param_1to1`        | Forward the first parameter received by the macro to the first parameter of the next (non-macro control) behavior.   |
| `&macro_param_1to2`        | Forward the first parameter received by the macro to the second parameter of the next (non-macro control) behavior.  |
| `&macro_param_2to1`        | Forward the second parameter received by the macro to the first parameter of the next (non-macro control) behavior.  |
| `&macro_param_2to2`        | Forward the second parameter received by the macro to the second parameter of the next (non-macro control) behavior. |

## Mod-Morph

Creates a custom behavior that triggers one of two behaviors depending on whether certain modifiers are held.

### Devicetree

Definition file: [zmk/app/dts/bindings/behaviors/zmk,behavior-mod-morph.yaml](https://github.com/zmkfirmware/zmk/blob/main/app/dts/bindings/behaviors/zmk%2Cbehavior-mod-morph.yaml)

Applies to: `compatible = "zmk,behavior-mod-morph"`

| Property         | Type          | Description                                                                       |
| ---------------- | ------------- | --------------------------------------------------------------------------------- |
| `label`          | string        | Unique label for the node                                                         |
| `#binding-cells` | int           | Must be `<0>`                                                                     |
| `bindings`       | phandle array | A list of two behaviors: one for normal press and one for mod morphed press       |
| `mods`           | int           | A bit field of modifiers. The morph behavior is used if any of these are pressed. |

See [dt-bindings/zmk/modifiers.h](https://github.com/zmkfirmware/zmk/blob/main/app/include/dt-bindings/zmk/modifiers.h) for a list of modifiers.

You can use the following nodes to tweak the default behaviors:

| Node     | Behavior                                  |
| -------- | ----------------------------------------- |
| `&gresc` | [Grave escape](../behaviors/mod-morph.md) |

## Sticky Key

Creates a custom behavior that triggers a behavior and keeps it pressed it until another key is pressed and released.

See the [sticky key behavior](../behaviors/sticky-key.md) and [sticky layer behavior](../behaviors/sticky-layer.md) documentation for more details and examples.

### Devicetree

Definition file: [zmk/app/dts/bindings/behaviors/zmk,behavior-sticky-key.yaml](https://github.com/zmkfirmware/zmk/blob/main/app/dts/bindings/behaviors/zmk%2Cbehavior-sticky-key.yaml)

Applies to: `compatible = "zmk,behavior-sticky-key"`

| Property           | Type          | Description                                                              | Default |
| ------------------ | ------------- | ------------------------------------------------------------------------ | ------- |
| `label`            | string        | Unique label for the node                                                |         |
| `#binding-cells`   | int           | Must match the number of parameters the `bindings` behavior uses         |         |
| `bindings`         | phandle array | A behavior (without parameters) to trigger                               |         |
| `release-after-ms` | int           | Releases the key after this many milliseconds if no other key is pressed | 1000    |
| `quick-release`    | bool          | Release the sticky key on the next key press instead of release          | false   |
| `ignore-modifiers` | bool          | If enabled, pressing a modifier key does not cancel the sticky key       | true    |

You can use the following nodes to tweak the default behaviors:

| Node  | Behavior                                     |
| ----- | -------------------------------------------- |
| `&sk` | [Sticky key](../behaviors/sticky-key.md)     |
| `&sl` | [Sticky layer](../behaviors/sticky-layer.md) |

## Tap Dance

Creates a custom behavior that triggers a different behavior corresponding to the number of times the key is tapped.

### Devicetree

Definition file: [zmk/app/dts/bindings/behaviors/zmk,behavior-tap-dance.yaml](https://github.com/zmkfirmware/zmk/blob/main/app/dts/bindings/behaviors/zmk%2Cbehavior-tap-dance.yaml)

Applies to: `compatible = "zmk,behavior-tap-dance"`

| Property          | Type          | Description                                                                                  | Default |
| ----------------- | ------------- | -------------------------------------------------------------------------------------------- | ------- |
| `label`           | string        | Unique label for the node                                                                    |         |
| `#binding-cells`  | int           | Must be `<0>`                                                                                |         |
| `bindings`        | phandle array | A list of behaviors from which to select                                                     |         |
| `tapping-term-ms` | int           | The maximum time (in milliseconds) between taps before an item from `bindings` is triggered. | 200     |
